Nigeria’s military has defended an attack on the north-east Nigerian city of Gombe by Boko Haram Islamic extremists.

Boko Haram fighters attacked a village in Chad, the first known lethal attack in that country by the Nigerian militant group, which killed several people including a local chief, according to residents and security forces.

Boko Haram militants have attacked a village inside Chad, their first deadly attack in the country, according to an army spokesman.